5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Priyanka Singh <priyanka.singh@xxxxxxx>
[ Upstream commit 9ec22ac4fe766c6abba845290d5139a3fbe0153b ]
Fix undefined behavior caused by left-shifting a negative value in the
expression:
cap_high ^ (1 << (bad_data_bit - 32))
The variable bad_data_bit ranges from 0 to 63. When it is less than 32,
bad_data_bit - 32 becomes negative, and left-shifting by a negative
value in C is undefined behavior.
Fix this by combining cap_high and cap_low into a 64-bit variable.
[ bp: Massage commit message, simplify error bits handling. ]
Fixes: ea2eb9a8b620 ("EDAC, fsl-ddr: Separate FSL DDR driver from MPC85xx")
Signed-off-by: Priyanka Singh <priyanka.singh@xxxxxxx>
Signed-off-by: Li Yang <leoyang.li@xxxxxxx>
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/20241016-imx95_edac-v3-3-86ae6fc2756a@xxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/edac/fsl_ddr_edac.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/drivers/edac/fsl_ddr_edac.c b/drivers/edac/fsl_ddr_edac.c
index 6d8ea226010d2..61e59341a41f9 100644
--- a/drivers/edac/fsl_ddr_edac.c
+++ b/drivers/edac/fsl_ddr_edac.c
@@ -331,21 +331,25 @@ static void fsl_mc_check(struct mem_ctl_info *mci)
* TODO: Add support for 32-bit wide buses
*/
if ((err_detect & DDR_EDE_SBE) && (bus_width == 64)) {
+ u64 cap = (u64)cap_high << 32 | cap_low;
+ u32 s = syndrome;
+
sbe_ecc_decode(cap_high, cap_low, syndrome,
&bad_data_bit, &bad_ecc_bit);
- if (bad_data_bit != -1)
- fsl_mc_printk(mci, KERN_ERR,
- "Faulty Data bit: %d\n", bad_data_bit);
- if (bad_ecc_bit != -1)
- fsl_mc_printk(mci, KERN_ERR,
- "Faulty ECC bit: %d\n", bad_ecc_bit);
+ if (bad_data_bit >= 0) {
+ fsl_mc_printk(mci, KERN_ERR, "Faulty Data bit: %d\n", bad_data_bit);
+ cap ^= 1ULL << bad_data_bit;
+ }
+
+ if (bad_ecc_bit >= 0) {
+ fsl_mc_printk(mci, KERN_ERR, "Faulty ECC bit: %d\n", bad_ecc_bit);
+ s ^= 1 << bad_ecc_bit;
+ }
fsl_mc_printk(mci, KERN_ERR,
"Expected Data / ECC:\t%#8.8x_%08x / %#2.2x\n",
- cap_high ^ (1 << (bad_data_bit - 32)),
- cap_low ^ (1 << bad_data_bit),
- syndrome ^ (1 << bad_ecc_bit));
+ upper_32_bits(cap), lower_32_bits(cap), s);
}
fsl_mc_printk(mci, KERN_ERR,
--
2.43.0
